Based on that one fact I could conclude that longer necks gave some males an advantage while other males adopted other fighting techniques."
Sure, but it seems pretty obvious (certainly not "circular") that longer necks in giraffes allowed them to eat leaves from taller trees, so natural-selection weeded out shorter necked giraffes from lands where they couldn't survive.
A little thought produces other advantages of giraffes' long necks:
- As you mentioned, male competition for territory & mates.
- The view from higher-up improves their ability to see both distant resources and near-by dangers.
- Giraffes' large size and high running speed makes adults impervious to most predators.
Nothing "circular" about any of those advantages.
csivils: "How do you know that Okapies necks are a result of where they live rather than they live where they do as a result of their neck?"
Of course, large animals do migrate long distances in search of greener pastures, but they also look for ways to exploit existing under-used resources.
So a giraffe which can stay-put by eating the tops of trees may be more likely to survive than one which must travel great distances for lower growing food.
Further, it's now thought the Okapi is the older species and that giraffes evolved from an extinct "transitional form" called Samotherium (middle between giraffe & okapi below).
csivils: "Take your answer and then explain to me how the subdivision that you live in determines your paycheck..."
No problem: the cost of living in your subdivision determines the lower limit on your paycheck -- if you can't afford it, you have to move out.
In that sense, the subdivision is exactly like the tall tree leaves giraffes eat: if giraffes are too short, they don't survive & reproduce in that environment.
Nothing "circular" about it, regardless of how often you make the claim.
csivils: "The fact you don't see it is circular is a short coming on your part, not a misunderstanding on my part."
No, there's nothing "circular" about my arguments, and the fact that you keep harping on that only says: 1) you misunderstand, perhaps deliberately and 2) you've been mis-educated into believing you can deny reality by yelling "circular" at it.
You can't.